Process for cleaning and corrosion protection of metals and a composition therefor



A ril 29, 1969 WATER TOLERANCE MLS. /1oo MLS OF SOLUTION WATER TOLERANCE 100 M9 OF UTI N P. A. ATTERBY 3,441,419 PROCESS FOR CLEANING AND CORROSION PROTECTION OF METALS AND A COMPOSITION THEREFOR Original Filed April 5, 1965 Sheet of 2 ZPHASES IPHASE O 1 i l I 1 l l l 400 420 440 460 I 483 500 520 MOLWEIGHT OF SULPHONATE 'I TS'Q'E O I 2 3 4 WEIGHT 'NVENTOR QOSOLUB'L'ZER F PER ALBINATTERBY MMwz/m ATTORNEYS A ril 29, 1969 Original Filed April 5, 1965 WATER TOLERANCE MLS/IOO MLS. OF SOLUTION P. A. ATTERBY 3, PROCESS FOR CLEANING AND CORROSION PROTECTION OF METALS AND A COMPOSITION THEREFOR Sheet i of 2 M OLECU LAR MOLECULAR WEIGHT waem 3o I HIGHER F SULPHONATE so 60 40 20 m l I 1 I I 0 20 40 6O 80 I00 LOWER SULPHONATE INVENTOR PER ALBIN ATTERBY ATTORNEYS United States Patent O 3,441,419 PROCESS FOR CLEANING AND CORROSION PRO- TECTION F METALS AND A COMPOSITION THEREFOR Per Albin Atterby, Skotvagen 7, Lidingo, Sweden Continuation of application Ser. No. 445,653, Apr. 5, 1965. This application Jan. 29, 1968, Ser. No. 703,518 Int. Cl. C23f 11/02, 15/00 U.S. Cl. 10614 9 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation of my application Ser. No. 445,653, filed Apr. 5, 1965, now abandoned.

The present invention relates to a process for cleaning and corrosion protection of metals or metal objects, especially fire arms, and to a corrosion inhibiting composition therefore of the type which usually is characterized as a temporary corrosion protecting agent. By this expression a product is meant which for instance by spraying, dipping or by painting is applicated on a metal surface for protection of the same against corrosion for a relatively short period of time. In general steel surfaces are the surfaces to be protected against corrosion. An essential property of said corrosion inhibiting agents is that the protective film formed can be removed by a conventional solvent.

A corrosion inhibiting agent of this known type usually consists of a solution in which ligroin is the solvent. The non-volatile base in such a corrosion inhibiting composition normally is present in an amount of 10-50% of weight and the major part of the same consists of a hydrophobic film forming substance, e.g., a mineral oil, a petroleum wax or wool fat. The base also contains corrosion inhibitors, e.g. petroleum sulphonate and water displacing additives, that is substances which by preferential adsorption displace water from a moist metal surface. The known corrosion inhibiting compositions sometimes also contain water in an amount of 0.5-% of weight together with so-called coupling agents of the type alkanols, glycols and glycol ethers which are added for obtaining a clear one phase system.

A protective film formed by such a corrosion inhibiting composition protects the covered surface for a certain period of time against the attack of atmospheric moisture. However, said film does not necessarily protect the object against a proceeding corrosion caused by electrolytes originally present on the surface, e.g. electrolytes originating from powder gases or when touched, so-called finger prints or finger marks, said corrosion inter alia being caused by the acid character of the skin secretion. When the corrosion is caused by the presence of acid compounds it is in many cases possible to counteract the same by the addition of a desactivator in the form of a weak base, e.g. an amine or an alkanol amine. The basic principle for such a conventional corrosion inhibiting composition is, however, that the components present are not compatible with water and form a hydrophobic protective film on the treated metal surface after evaporation of the volatile components. Thus, with the ice use of e.g. petroleum sulphonates as corrosion inhibitors the water insoluble barium, calcium or magnesium salts have been chosen.

However, the magnitude and the intensity of the corrosion attack depends on the concentration of the electrolyte in the extremely thin layer consisting of an aqueous solution, which layer covers the surface or parts thereof. Upon dilution this action is decreased and also by a short rinsing with liquids of a high water content the electrolyte can be removed practically completely. However, known corrosion inhibiting agents of the above kind are not very suitable for such a treatment of metal surfaces. Primarily this depends on the fact that the water content of the corrosion inhibiting compositions is completely insufiicient. Even if they would admit a water content of up to 10% weight the result would be unsatisfactory.

The present invention is based on the principle that not only grease and oils but also water soluble substances must be soluble in the corrosion inhibiting composition so that they can be removed by rinsing with the composition. For this purpose the hydrophobic properties of the remaining protective film have to be sacrificed but in spite of this it has been possible to attain an improved protective action.

The cleaning and corrosion inhibiting composition according to the invention is a clear or slightly opalescent colloidal solution consisting of water and a hydrocarbon solvent with a boiling point or boiling range of 60-260 C., suitably of the ligroin or Stoddard solvent type, and dissolved non-volatile film forming components comprising one or more corrosion inhibitors and solubilizing agents.

The process according to the invention for cleaning and/or corrosion protection, especially of fire arms, is characterized by treating the objects to be cleaned and/ or corrosion protected with a composition comprising:

(a) 15-50% of weight of a hydrocarbon solvent,

(b) 10-50% of weight of water,

(c) 6-20% of weight of at least one hydrophilic as well as lipophilic sulphonate of sodium, potassium, lithium, ammonia, the sulphonic acid having a mean molecular weight within the range 400-540,

((1) 0.l-6% of weight of a di or triethanol amine salt of a carboxylic acid with the general formula phenylRCOOH, in which R is a saturated or unsaturated hydrocarbon group with a straight chain containing 0-3 carbon atoms, and

(e) 0.l-6% of weight of a nonionic water soluble emulsifier consisting of an ester of oleic acid or ricinoleic acid with an ethylene oxide adduct of a glycol or a hexitol, the hydrophilic part of the emulsifier having a molecular weight within the range 200-1400.

Petroleum sulphonates are suitable for use as component (c) and they are obtained by sulphonation of petroleum fractions with subsequent neutralization with the above-mentioned bases. Depending on the origin of the petroleum fraction the chemical constitution of the sulphonates may vary, but an essential component is usually alkyl aryl sulphonates having 18-28 carbon atoms. The products obtained from petroleum are usually, on account of their colour, called mahogany sulphonates. Commercially available products usually contain about 40% of mineral oil. Such products may be used according to the invention and the presence of the mineral oil is then usually acceptable or even of advantage. However, it is also possible to use sulphonation products of alkyl aryl hydrocarbons obtained in other ways.

Further to the above-mentioned components the composition may also contain one or more of the following additives for alteration of the physical properties of the total composition or of the protective film left upon evaporation of the volatile components or for further increasing the corrosion protective action or the water retention power, the composition comprising the additives defined below being liquid and without crystalline precipitation at the temperature of use:

(f) 120% of weight of a monoester of a monohydric alkanol having 1-16 carbon atoms with a monocarboxylic acid having 18-2 carbon atoms or a diester of a monohydric alkanol having 1-16 carbon atoms with a dicarboxylic acid having 4-10 carbon atoms (for decreasing the viscosity of the remaining protective film and/ or for dissolving sulphonates),

(g) -20% of Weight, preferably 28%, of diethylene glycol or triethylene glycol (for decerasing the viscosity of the remaining protective film),

(h) 0-10% of weight of an alkanol having 1-4 carbon atoms or of an alkane diol having 2-6 carbon atoms or a monoether of the above-mentioned alkane diols,

(i) 03% of weight of a cyclic diether such as dioxane (for decreasing the viscosity of the total composition).

The composition according to the invention is normally a clear or slightly opalescent solution within a temperature range of usually from about 70 C. to about -8 C. Below and above said interval a turbidness may occur depending on precipitation of one or more of the components. However, such a precipitation disappears when the temperature is changed to a value within the above range. The occurrence of such precipitation apparently does not decrease the cleaning or corrosion inhibiting effect of the composition.

In order to make the composition a clear solution it is necessary to maintain a good balance between hydrophilic and lipophilic components. Within the above-mentioned ranges for the components it is thus possible to obtain compositions which are not completely clear or which have a minor or major amount of precipitations. To re-install the balance in such cases for obtaining a clear or slightly opalescent solution is, however, within the capacity of the average expert in the field, and the required contents can easily be determined by simple experiments.

Petroleum sulphonates are active corrosion inhibitors also in moderate concentrations and with a view to this action they are not required in a great amount. The petroleum sulphonates chosen have, however, also a distinct ability to solubilize water and this action is increased with their concentration. Within the molecular range stated the best result is obtained with sulphonates having a molecular weight of 400 or somewhat thereabove. With the use of only one sulphonate and in the presence of component (e) above as a co-solu'bilizer it is possible to attain a water content of about 30% or more. Still higher water contents up to 50% or even more are possible with the use of a mixture of two sulphonates with a molecular weight difference of at least 15 and in the presence of component (e) as a co-solubilizer. Especially good results are obtained with a molecular weight difference of 30 or more.

In order to decrease the viscosity of the corrosion inhibiting composition and to increase the temperature range, within which the composition is a clear or only weakly opalescent solution, it is, as has been mentioned above, suitable to add up to 10% of weight of an alkanol having 1-4 carbon atoms or an alkane diol having 2-6 carbon atoms or a monoether of the above-mentioned alkanols with some of the alkane diols (optional component (h) A cyclic ether such as dioxane can also be used for decreasing the viscosity, usually in amounts of up to 2-3 of weight (optional component (i) The consistence of the film remaining after the evaporation of the solvents can also be decreased by the addition of diethylene or triethylene glycol (optional component (g)). The film then becomes softer and more oily but it is still sticky and adherent. Up to 20% of weight of such a compound can be present in the corrosion protecting composition without any deleterious effect. For the most purposes 1.5-l0.0% of weight is a suitable content. A similar result as regards the consistence of the remaining film may be obtained by adding to the composition a monoester of a monohydric alkanol as defined sub (f) above.

As has been mentioned above the commercially accessible petroleum sulphonates are usually dissolved in a lubricating mineral oil. Said oil-containing products are usually well usable for the preparation of the compositions according to the invention. The lubricating mineral oil then functions as a lubricating and film forming component. However, the lubricating mineral oil decreases the Water tolerance and it may often be advantageous to add the sulphonates in a pure form or dissolved in a solvent more polar than mineral oil. A suitable such solvent is a monoester of a monohydric alkanol having 1-16 carbon atoms with a monocarboxylic acid having l82 carbon atoms or a diester of a monohydric alkanol having ll6 carbon atoms with a dicarboxylic acid having 4-10 carbon atoms (optional coponent(f)). The corrosion inhibiting composition according to the invention can without any change of the water tolerance contain up to 20% of weight of such a mono or diester. When petroleum sulphonates dissolved in a lubricating mineral oil are used in the corrosion inhibiting composition according to the invention it may be of advantage to add an ester of the said type, because such addition decreases the stickiness of the surface film and makes it more lubricating.

The effect according to the invention relating to the water tolerance is further elucidated by the enclosed drawings.

FIG. 1 shows the change of the water tolerance with the mean molecular weight of the petroleum sulphonate for a solution containing components (a) and (c), viz. Stoddard solvent or ligroin with dissolved commercial petroleum sulphonate (containing about 40% of lubricating mineral oil). This solution contains 18% of weight of a mineral oil solution with 62% of weight of petroleum sulphonate.

FIG. 2 shows the increase of the water tolerance by the addition of a co-solubilizer consisting of polyoxyethylene sorbitan monooleate in admixture with triethanol ammonium benzoate in the weight proportions 48:52. The addition of petroleum sulphonate is the same as the one illustrated in FIG. 1. The curve 1 shows the solubility change with the use of a sodium petroleum sulphonate having the molecular weight 455 and the curve 2 shows the water solubility change with the use of a mixture consisting of two parts of sodium petroleum sulphonate with the molecular weight 455 and one part of sodium petroleum sulphonate with the molecular weight 470.

FIG. 3 relates to a solution of mixtures of sodium petroleum sulphonates dissolved in ligroin, the sulphonates also in this case being added in the form of commercially accessible 62% solutions of the sulphonate in question in a lubricating mineral oil. All added mixtures of mineral oil sulphonate solution comprises 118% by weight of the ligroin solution. The curves 1-5 each relate to a mixture of two commercial petroleum sulphonates of a different molecular weight. The curves show the water tolerance of the solution depending on as well the molecular weight of the petroleum sulphonates as the weight proportions of the same within each mixture. From the curves it can be seen that petroleum sulphonates of the lower molecular weights give a greater water solubility (water tolerance) than those with a higher molecular weight, that a mixture of two different sulphonates (with a maximum of about 60% of weight of the low molecular component) in an essential part of the mixing range gives a higher water solubility than the individual mixture components and that mixtures with a great difference between the molecular weights of the sulphonate components give a higher maximal solubility. The latter effect is for instance illustrated by comparison bet-ween the curves 2 and 3, representing the molecular weight difference 50 and 95 P t f, h f respectively and the curve 4, representing the molecular WT weight difference 15. T1 b Thecprrosion The preparation of the corrosion inhibiting composition g gfig gggggggg according to the invention can be made in several manners. It is most suitable to dissolve in the organic solvent 7 6 4 7 all components which are soluble in the same. This re- 4 2 1 lates primarily to the sulphonate or sulphonates which 3; are added prior to the water either in a pure form or 5 5 3:4 predissolved in another solvent. Mainly water soluble z zggg 48) 10.2 2.1; components, such as di or triethanol amine together with g? f g f g F Sultably i All compositions according to Examples 2-6 possessed, 1580 a 6 Water or a F some 0 t e after dilution with water to a clear or slightly opalescent fi as 1 f t e 50 n solution, desirable cleaning properties and after the evape ceanmg or COIYQSIOH pfotectloni y 10 oration of volatile components a corrosion preventing of fire arms, according to the invention the composition protective film was formed according to the invention is applicated conventionally on V n V the ob3ects to be treated, e.g. by spraying, dipping, brush- Examples 6 and 7 Example 6 Example 7 ing or similar. The composition is usable on common C t om 0118 SI metals: especlany steels toddai-d solvent 30 00 23,00 The petroleum sulphonates used in the following examgi Y d pa 45 5.00 ples are in all cases commercial products which, as has gi ffig fiifii :62 23% been mentioned above, consist of a mixture with or disg -suipg az i ularw sll 3.53 1 53 solved in a mineral oil. The content of sulphonate is in f 'jg gflgigf g331 1333 3 all instances 62% of weight, calculated on the amount 25 ater n, 38.60 35.75 t t d Triethanolamine 1.50 1.50 s a e Benzoic acid 1. 15 1.15

The following basic solutions were prepared: Data:

Water tolerance, nil./ 100 mls =10 36 Cloud point, 0.: Parts of weight Upptr +70 +70 Lower =8 8 Component 1 2 3 4 5 Evaporation film Example 1: 1 Greasy at 25 C., slightly tacky.

Na-petroleum sulphonate (mo- 2 Oily, fluid at 25 (3., not tacky. Nlecutlarlweight %5.?1) t 9. 2 9. 2 9. 2 9. 2 9. 2

21-118 ['0 euni S11 10 0H3 e 1110" Dleelular weight 470) 4.0 4.0 4.0 4.0 EXAMPLE 8 t i l 1.5 1.5 1.5 1.5 r ii g i fifig ti" 3,0 3,0 3,0 3,0 3,0 In order to demonstrate the importance of the water g ggg 3g %8 3-8 2-8 content in the composition of the invention for cleaning h'gQjjjjjjjj 315 5 i vigcose solutions and corrosion protection of metal objects covered with corwatertoleranceimkrosion promoting salts the following experiments were Viscosity very viscous decreasing viscosity made 40 Experiment a.Cylindrical rods of carbon steel were T1113 eXample Shows the VlSeOsltY deefeaslng action of placed in a support and were shot at with 6.5 mms. rifle all addltlon Of a Inlnof amount of dlOXane Y a mlnor ammunition from which the bullets had been removed. Change Of the dlOXane Content the vlscoslty can be The individual rods were first rinsed for 60 seconds in Justed t0 ye s rable value. solutions with different increasing water contents and then All compositions Possessed deslrable cleanlng Propertles with petroleum either and were subsequently allowed and after the evaporatlon 0f Volatlle components a to corrode under a thin layer of water for 75 minutes at T0510n lnhlbltlng film Was tofmei room temperature. After drying the following corrosion results were obtained.

Table I Percent of weight 01- Th Water content of the e COITOSIOH The basic inhibiting agent, P Corrosion attack solution composition 0 Heavy corrosion. Examplem 5 Heavy corrosion.

kigroit'lul 44 35.2 5 15 Moderate corrosion.

a- 8 f0 eum S11 ona e 1110 ecu 3-1 wgi ht4 32 2% 45 N0 corroslonriethano ammonium enzoate poiyoxyethyiepe Sorbitan monooieate 5 4 Experiment b.Three sand blasted and thoroughly {,gggf g g fi g t 6 3-; cleaned plates of carbon steel (75 x 40 x l mms.) were Example 3; covered with a synthetical salt solution which was dried Ligroin 40 32 Nametmlem sulphonate (molecular rapidly by IRhirradiation One of the plates was then Weight420) 17 13.6 painted with t e composition according to Example 3, agfgfig g Sulphwate (molecular 10 8 whereas the others were treated with conventional gun Diethanol amiiib'riiiii'ri 15. 31345525113123: 4 grease and conventional gun preservative oil respectively. Polyoxyethylene sorbitan monooleate. Water (water tolerance 68) 40 The three plates were stored in a cold shed for 4 Weeks, p 43 34 4 whereafter the following corrosion results were obtained.

igrom N sulphonate (molecular Nweight1420) i i1 15 12 Table a-petro eum SL1 p onate mo 9CD. ar

Weight 510) 6 is Corrosion agent. Corrosion attack Trielt hanol amtiln(iniuriogignarnatia"Z 1.2 2 70 Gun grease Heavy corrosion.

o yoxyet yeneiricino ea Diethyleneglycol 3 M Gun preservative oil Heavy corrosion. glutyl i mL... 7 -2 Composition according to Examgig g 290 ple No corrosion.

igroin Na-petroleum sulphonate (molecular What IS claimed 15. I

weighty-2) 1. A process for cleaning and corrosion protection of metal objects, especially fire arms, comprising treating the metal objects with a composition consisting essentially (a) 15-50% by weight of a hydrocarbon solvent boiling in the range of 60 to 260 C.

(b) 10-50% by Weight of water, '(c) 6-20% by weight of at least one sulphonic acid salt, the cation of which is selected from the group consisting of sodium, potassium, lithium, ammonium, the sulphonic acid having a mean molecular weight in the range 400-540,

(d) 0.1-6% by Weight of an amine salt selected from (e) 0.l-6% by weight of a nonionic, water soluble emulsifier consisting of an ester selected from the group consisting of esters of oleic acid and ricinoleic acid with an ethylene oxide adduct selected from the group consisting of a glycol or a hexitol, the hydrophilic part of the emulsifier having a molecular weight within the range 200-1400.

2. A process for cleaning and corrosion protection of metal objects, especially fire arms, comprising treating the metal objects with a composition consisting essentially of (a) 15-50% by weight of a hydrocarbon solvent boiling in the range of 60 to 260 C.

(b) 10-50% by weight of water, (C) 10-30% by weight of a mixture containing about 40% of mineral oil and about 60% of petroleum sulphonates, the cation of which is selected from the group consisting of sodium, potassium, lithium, a mmonium, the sulphonic acid having a mean mo1ecular weight in the range of 400-540.

(d) O.l-6% by weight of an amine salt selected from the group consisting of diethanol amine salts and triethanol amine salts of a carboxylic acid With the general formula phenyl-RCOOH, in which 'R is selected from the group consisting of saturated hydrocarbon radicals and unsaturated hydrocarbon radicals with a straight carbon chain containing -3 carbon atoms,

(e) OJ-6% by weight of a nonionic, water soluble emulsifier selected from the group consisting of esters of oleic acid and ricinoleic acid With an ethylene oxide adduct selected from the group consisting of glycol and hexitol, the hydrophilic part of the emulsifier having a molecular weight within the range 200-1400.

3. A process for cleaning and corrosion protection of metal objects, especially fire arms, comprising treating the metal objects with a composition according to claim 1 which also contains at least one of the following optional additives:

(a) 1-20% by weight of an ester selected from the group consisting of a monoester of a monohydric alkanol having 1-16 carbon atoms with a monocarboxylic acid having 18-2 carbon atoms and a diester of a monohydric alkanol having 1-16 carbon atoms, with a dicarboxylic acid having 4-10 carbon atoms,

(b) 020% by weight, preferably 2-8%, of a glycol selected from the group consisting of diethylene glycol or triethylene glycol,

(c) 0-10% by weight of a hydroxy compound selected from the group consisting of an alkanol having 1-4 carbon atoms, an alkane diol having 2-6 carbon atoms and a monoether of an alkane diol having 2-6 carbon atoms, and

(d) 0-3% by weight of a cyclic diether.

4. A process for cleaning and corrosion protection of metal objects, especially fire arms, comprising treating the metal objects with a composition according to claim 2 which also contains at least one of the following optional additives:

(a) l-20% by weight of an ester selected from the group consisting of a monoester of a monohydric alkanol having 1-16 carbon atoms With a monocarboxylic acid having 18-2 carbon atoms and a diester of a monohydric alkanol having 1-16 carbon atoms, with a dicarboxylic acid having 4-10 carbon atoms,

(b) 0-20% by weight, preferably 2-8% of a glycol selected from the group consisting of diethylene glycol and triethylene glycol,

(c) 0-10% by weight of a hydroxy compound selected from the group consisting of an alkanol having 1-4 carbon atoms, of an alkane diol having 2-6 carbon atoms and a monoether of an alkane diol having 2-6 carbon atoms, and

(d) 0-3% by weight of a cyclic diether such as dioxane.

5. A cleaning and corrosion inhibiting composition as defined in claim 1.

6. A cleaning and corrosion inhibiting composition as defined in claim 2.

7. A cleaning and corrosion inhibiting composition as defined in claim 3.

8. A cleaning and corrosion inhibiting composition as defined in claim 4.

9. The process of claim 1 wherein said sulphonic acid salt is a petroleum sulphonate.

References Cited UNITED STATES PATENTS 2,402,793

J'ULI'US FROME, Primary Examiner. L. HAYES, Assistant Examiner.

US. Cl. X.R. 

